My current nick, Choma comes from some scifi books: The Nights Dawn Trilogy by Peter F Hamilton ( https://en.wikipedia.org/wiki/The_Night's_Dawn_Trilogy ). The character Choma is a sentient bitek construction that holds an imprint of someone centuries dead (the culture transfers all memories of those who die into a communal AI construct). The bitek Sergeant was created in response to the badddie from the books, and the possessed souls taking over planets.
Ive always pronounced it Coma, which was a good choice, coz i did love to get blackout drunk back then
My previous name on MTA was SangDrax which again comes from a book series: The Death Gate Cycle by Margaret Weis and Tracy Hickman ( https://en.wikipedia.org/wiki/The_Hand_of_Chaos ). Sang-Drax was a weird serpent humanoid who worked with elves as a ship captain/bounty hunter.
Ive used both of these names in gaming for about a decade and a half - Choma seems relatively unique, so i usually use that.
(Oh, and if im roleplaying a female RPG character, i usually go with the name Ephilia - red haired dual wielding fighter/thief - its a distortion of Ophelia - https://en.wikipedia.org/wiki/Ophelia )